The long-term goal of this research project is to understand the molecular basis of cell motility, especially how actin filaments are assembled in vivo and how their assembly contributes to the control of cell shape and movement. The investigator's approach to this goal is to study how actin-binding proteins control actin assembly in vitro and in vivo. The investigator's continue their focus on capping protein, which binds to barbed ends of actin filaments. Capping protein (CP) is ubiquitous among eukaryotes. The investigator's work on specialized cell systems indicates that capping protein does function to control actin assembly and cell motility in vivo and this application proposes to extend those studies to more complex and interesting systems. In addition, study of CP has uncovered a novel form of cell motility, which they propose to investigate.